Roast the vegetables and grill the steak. Baste the onions and potatoes with 4 tbsp olive oil. Add pepper to taste. In a grill pan (or BBQ/oven 450°F*), grill the vegetables over medium-high heat, turning from time to time, until cooked through and lightly charred – about 5-8 min (depending on the method). Add the beef strips during the last 3-4 min of cooking and grill 1-2 min on each side. *Cooking with the oven might take longer.